1. Field of the Invention
The present invention relates to a blood vessel puncturing device using ultrasound waves and, in particular, to a blood vessel puncturing device which enables easy and accurate insertion of a puncturing needle into a blood vessel of a subject body for blood gathering or medical fluid injection.
2. Description of the Prior Art
FIG. 6 shows a blood vessel puncturing device similar to that described in "Linear Scanning Probe for Superficial Portion" printed in the Japan Ultrasound Medical Institute Lecture Collection 57-300 (October and November, 1990).
In FIG. 6, numeral 21 denotes an ultrasound probe for transmitting and receiving ultrasound waves, 22 a solid attachment, 23 a puncturing needle and 24 a subject body. The solid attachment 22 is provided between the ultrasound probe 21 and the subject body 24, and the puncturing needle 23 is stuck into the subject body 24 via the solid attachment 22.
On the other hand, FIG. 7 shows a blood vessel puncturing device similar to that described in U.S. Pat. No. 5,261,409 (equivalent to JP-A5-168636).
In FIG. 7, the blood vessel puncturing device comprises an ultrasound probe 31 and a housing 32 which holds a puncturing needle. The ultrasound beam emitted from the ultrasound probe 31 is reflected off a reflector 33 provided in the housing 32 so as to enter a subject body in parallel to a needle holding hole 34 formed through the housing 32 and the reflector 33. Then, the ultrasound waves reflected from the subject body are reflected off the reflector 33 so as to be received at the ultrasound probe 31. A blood vessel is located based on the Doppler effect so that the puncturing needle is inserted into the needle holding hole 34 and stuck into the located blood vessel.
However, in case of the scanning probe shown in FIG. 6, since the solid attachment is used, it is necessary to press the solid attachment onto the surface of the subject body applying a certain force for tightly contacting the solid attachment with the subject body whose surface shape is not constant. This causes deformation of a superficial blood vessel so that the puncturing needle can not be precisely stuck into the blood vessel. Further, since an angle between the puncturing needle and the surface of the subject body is set not less than 45 degrees when sticking the needle into the subject body, it is difficult to stick the needle with accuracy into a blood vessel, particularly a fine blood vessel, extending in parallel to the surface of the subject body.
On the other hand, in case of the blood vessel puncturing device shown in FIG. 7, since no fixing means is provided for the device, it is possible that the device itself moves when sticking the needle into the blood vessel. Further, since the insertion depth of the needle into the subject body can not be known, the needle can not be precisely stuck into the blood vessel.